I would download Firefox from Mozilla and see if sync works for you. https://www.mozilla.org/en-US/firefox/all/#product-desktop-release Download, unzip, and run firefox-bin from the folder.

I notice that you have a weird user agent set via the override pref. general.useragent.override:

• Mozilla/5.0 (X11; Slackware Linux x86_64; rv:111.x) Gecko/20100101 Firefox/111.x

Can you login to the Firefox account via this web page?

• https://accounts.firefox.com/signin
• https://accounts.firefox.com/settings

You can create a new profile as a quick test to see if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

If the new profile works, you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

Hello again...

Thanks for the rapid replies.

Firstly, @jonzn4SUSE...

> I would download Firefox from Mozilla...

It doesn't work that way in GNU/Linux, my friend. Packages are custom made for every distribution of Linux. In Slackware, it requires me to "build" the application from the binary download. This is what I do to run the latest FF on my Slackware; otherwise, the versions of FF in the Slackware repositories are older ESR versions.

Anyway, as stated above, I "build" these FF each time there is an update, then I upgrade my current FF to the newest version. This has worked for me for a decade or so. I have never experienced an issue (that I could not easily resolve) with FF before. This particular issue just started with v12.0.2. The version just prior to that one was the last time Sync would login.

If I have to, I guess I could revert to the actual FF ESR version that Slackware utilizes. I really don't want to do this because that ESR is quite "dated" compared to the newest FF.

Thanks for your suggestions, though. :)

___

@cor-el said,

> I notice that you have a weird user agent ...

Yes, I do have a custom useragent string. And now that you mention it, in the past I have had some flakey issues on some webpages and had to adjust that useragent accordingly.

I cannot login to any Mozilla pages at this time with FF. This started the same time that the Sync issue started. Yet, with v12.0.1, all was fine and dandy.

Just to see... I'm going to revert to the standard useragent in FF and see what happens.

Stand by...

OK, I've made a little progress. I usually manually update my useragent when FF changes to a new version. I had forgotten to do this. I upgraded the useragent to:

Mozilla/5.0 (X11; Slackware Linux x86_64; rv:13.x) Gecko/20100101 Firefox/13.x

I can now login to Mozilla sites again. Unfortunately, even though I do get the sync login page to come up properly now, when I try to login there, a "working" notification pops up and spinner spins and spins and spins.

Well, that's progress, anyway. I also manually deleted the previous Mozilla and Firefox persistent login cookies. No help. I turned my Cookie setting from strict to standard. No help. I also added accounts.firefox.com to my protected cookies. No help.

Interesting... I'll keep tinkering around with it. If I finally do resolve it, I'll post back here so others may benefit from my experience. Thanks to both of you above for the replies and suggestions.

Regards,

~Eric

Listen, folks... I'm going to mark this as resolved (for the most part).

To be honest, I don't need Sync, anyway. It was handy when I had multiple machines, but I only have one these days, and I have my manual backups to fall back on with regards to Firefox's data.

I LOVE Mozilla! Keep up the wonderful work! I would hate to not have FF and my Thunderbird; particularly the latter, because there is no decent stand-alone email client out there these days that works as well as and has as many features as TB.

Cheers!

~Eric

Note that for Firefox 11x versions (110-119) the rv segment has been frozen to rv:109 in case a website mistakenly parse this as IE 11.

• 1805967 - Freeze `rv:` segment in the User Agent string to `rv:109.0` to avoid erroneous IE11 detection

Thank you, @cor-el...

I've made the suggested fix to the useragent: Mozilla/5.0 (X11; Slackware Linux x86_64; rv:109.0) Gecko/20100101 Firefox/113.0

I was having some buggy issues on a couple websites, but...

...ALL seems to be Happy now. :)

~E.

Hey, friends... it's me again!

My Firefox Sync issues were "automagically" fixed by upgrading to v114 just now. So, YAY! :) That confirms for me that this was not an issue on my side. There was something amiss re: FF Sync with v112.0.2 through v113.0.2, evidently. It didn't seem to affect everyone, but it sure affected me. All's well now, though.